In the prior-art there are devices, using steam or water scrubbing, which are used to remove particulates from exhaust gasses. While these devices are effective to some degree in removing particulates and gasses from exhaust gas streams, stricter standards for exhaust emissions have created a need for more efficient pollution removal.
Furthermore, many devices of the prior art include moving parts, e.g., dispersing wheels, fans, and the like, which contributes to the building and maintaining costs of the device. In addition, many have a specialized structure and can only be applied to certain exhaust or waste-gas systems and not to existing installations without extensive rebuilding.
In Chemical Engineers' Handbook (5th Edition) by R. H. Perry, and Cecil H. Chilton, on pages 20-94 to 20-103 are disclosed various gas scrubbers which use water sprays for removing particulates from gas streams. Adding steam to the aerosol created by the water spray is also disclosed. (See page 20-96.)
U.S. Pat. No. 3,139,331 to Boudreau discloses a smoke cleansing apparatus in which the smoke is wetted with water or steam while being directed through a coiled duct. Centriftigal force causes the smoke particles to be carried away by the condensed steam to a discharge port.
U.S. Pat. No. 3,582,051 to Klein discloses a smoke cleaning apparatus wherein smoke is first directed through conical baffle of closely spaced overlapping rings, which holds back larger particles, and then through helical baffles where an apertured spray pipe sprays water to cool the smoke and fumes and entrap further particles in the smoke.
U.S. Pat. No. 3,605,386 to Erwin discloses a pollution eliminator comprising a section with steam injectors followed by a section with water injecters. In the steam injector section, baffles confine the exhaust to ensure saturation of exhaust solids.
U.S. Pat. No. 3,920,423 to Ross discloses a steam scrubber comprising steam injecters, which inject steam from a conduit in the center of a tank through which smoke is directed.
U.S. Pat. No. 3,888,642 to Toyama discloses an exhaust-stack scrubber attachment comprising a steam jet for mingling the exhaust stream with steam upstream from off-set filter baffles.
U.S. Pat. No. 4,017,277 to VanDyke, Sr. et al. discloses a direct contact water heating system that comprises transferring heat to water from flue gasses and stripping the water of dissolved gasses with steam.
U.S. Pat. No. 4,113,453 to Rector discloses an anti-pollution device comprising a nozzle directing steam upwardly into stack, with a series of cooling chambers to condense pollutant containing steam above the nozzle.
U.S. Pat. No. 4,624,190 to Cappi discloses an apparatus for disposal of flue gas that scrubs the flue gas with water from nozzles.
In some prior art devices, the water or steam is mechanically dispersed in the path of smoke. For example, U.S. Pat. No. 750,351 to Doyle discloses a device for removing smoke, which comprises water jets directed upwardly with sprayer or spreader plates above the jets to deflect the water spray downward.
U.S. Pat. No. 4,257,792 to Cremo discloses a stream-pressured smoke eliminator that comprises a steam supply fed to a steam-jet-operated star wheel. The star wheel dispenses a sheet-like layer of steam to intercept smoke rising through the eliminator. The eliminator can be assembled as a unit, which is inserted into a smoke-stack by means of a helicopter.
U.S. Pat. No. 3,760,567 to Stalker discloses a smoke cleaner that uses extractor fans to draw the smoke upward. Water is directed to the underside of the fan, which sprays the water outwardly in a spray. Steam or hot water may also be directed against the fan to remove heavy pollution constituents such as oils and tars (col. 3, lines 53 to 68).
Another device for mechanically dispersing a water stream is disclosed in U.S. Pat. No. 1,537,065 to Burdin, which describes a humidifier comprising a water nozzle and an angularly disposed adjustable target plate. In operation, water under pressure impinges against the deflecting plate and breaks the water into a spray. The outer line of the spray, after striking the bottom of the chamber, may rebound and break up further. (See page 2, lines 52 to 59).